1. Technical Field
The present invention relates generally to mobile communication systems and, more particularly, to high speed data packet networks for delivering data to mobile terminals.
2. Description of the Related Art
The general packet radio service (GPRS) is a non-voice value added service that allows information to be sent and received across a mobile telephone network. It supplements, or rides on top of, today's circuit switched data and short message service (SMS) networks. The theoretical maximum speed of GPRS systems includes speeds of up to approximately 171.2 kilobits per second (Kbps). This maximum speed is achievable in GPRS systems using all eight timeslots at the same time in a time division multiple access (TDMA) context.
This speed is about three times as fast as data transmission speeds possible over today's fixed telecommunication networks and ten times as fast as current circuit switched data networks on Global System for Mobile Communications (GSM) standard TDMA networks. Thus, GPRS systems are advantageous in that they require less system resources to transmit a fixed amount of data in comparison to using a traditional circuit switched approach. By allowing information to be transmitted more quickly, immediately, and efficiently across the mobile network, GPRS may well be a relatively less costly mobile data service compared to short message service and circuit switched data networks.
General packet radio service also facilitates instant connections in which information can be sent or received immediately as the need arises, subject to radio coverage. No dial-up modem connection is necessary. GPRS, similar to some broadband connections for personal computers, is often referred to as being “always connected”. Thus, another one of the advantages of GPRS is that data may be transmitted immediately, whenever the need arises. In contrast to circuit switched data networks in which a connection must be established to transmit a data packet or data file, GPRS operation is extremely efficient in those situations in which a small amount of data is to be sent.
The emphasis of many designs today are to create wireless computer networks and to connect data devices, including personal computers to wireless transceivers and mobile terminals. A system that provides instantaneous response is very important for time critical applications and, more generally, for the implementation of wireless computer networks.
For example, a remote credit card authorization system implemented in a wireless network can be greatly improved if it is unnecessary for the customer to wait the amount of time that is required to establish a connection. Anyone that has waited at a cash register for credit authorization while a modem dials in and transmits account information can readily appreciate this advantage.
Additionally, GPRS facilitates the use of Internet applications not only from personal computers, but also from appliances and machines. It is anticipated that appliances will be designed to be coupled to the Internet to facilitate control either onsite or remotely. While some people envision connecting these appliances to a network port by physical lines, it would clearly be advantageous to be able to connect such appliances to the Internet through a wireless link. GPRS will facilitate the creation of Internet controlled appliance networks through a wireless medium.
As suggested before, GPRS involves overlaying a packet based air interface on an existing circuit switched wireless network. For example, the circuit switched wireless network may comprise a GSM network. Accordingly, the user is given an option to utilize a packet-based data service. In order to overlay a packet-based air interface over a circuit switched network, the GPRS standard defines new infrastructure nodes to minimize the impact to existing networks in terms of hardware and software.
Other packet-based systems are being developed for delivering data to wireless terminals. For example, universal mobile telecommunications systems (UMTS) are being developed to provide the benefits of GPRS with added benefits, including faster speeds and greater throughput. While GPRS systems have been developed to supplement and enhance existing voice based wireless communication networks, UMTS networks are new and are expected to be launched in the near future.
Another advantage of high speed data networks such as GPRS and UMTS is that the packet switching that results from the infrastructure nodes allows the use of GPRS radio resources only when users actually are sending or receiving data. Unlike traditional circuit switched voice networks, a connection is not continuously reserved for a user for the intermittent transmission of data. This efficient use of scarce radio resources means that a larger number of GPRS users can share the same bandwidth and be served from a single base station or cell. The actual number of users that may use the system at one time, of course, depends on the amount of data being transferred.
One problem that the inventors have realized with respect to high speed GPRS/UMTS networks relates to the interaction of a gateway GPRS support node (GGSN) and the various application servers that deliver data to wireless terminals through the data packet network, such as the Internet, and the wireless high speed data packet networks such as GPRS/UMTS. Typically, a gateway GPRS support node (GGSN) communicates with the application servers by way of the Internet and provides the gateway functionality to the GPRS/UMTS networks. There is a need, therefore, for a system and method that enables the network, and more specifically, the application servers that are external to the high speed wireless networks, to more intelligently assign a quality of service rating for a given session to reduce overloading and improve network performance.
The inventors have realized that the external application servers make quality of service determinations based upon the service level agreements with users but do not account for network conditions in the high speed wireless data packet networks, such as GPRS/UMTS networks. Accordingly, the application servers may waste resources by attempting to provide a quality of service that cannot be supported by the GPRS/UMTS networks.